Process of producing carboxylic acid chlorides



Patented Aug. 10, 1943 UNITED STATES PATENT OFFICE PROCESS OF PRODUCINGCARBOXYLIC ACID CHLOE-IDES Morris S. Kharasch and Herbert G.- Brown,Chicago, Ill., assignors to E. I. du Pont de Nemours & Company,Wilmington, Del., a corporation of Delaware No Drawing. Originalapplication February 12,

1940, Serial No. 318,649. Divided and this application December 4, 1942,Serial No. 467,912

2 Claims. (01.260-544) This invention relates to a new process offorming carboxylic acid chlorides, and more particularly to the use ofoxalyl chloride to produce said carboxvlic acid chlorides.

This application is a division of our copending' 5 application, SerialNo. 318,649, filed February 12, 1940.

This invention has as an object to provide a new process of formingcarboxylic acid chlorides.

A further object is to develop a new use for oxalyl l0 chloride. A stillfurther object is to maintain reaction conditions which enable oxalylchloride to react with organic compounds to produce carboxylic acidchlorides. A still further object is to provide a novel and easilyconducted process 15 of making carboxylic acid chlorides which can beconverted into carboxylic acids by hydrolysis.

Other objects will appear hereinafter.

These objects are accomplished by the following invention according towhich an organic com- 2 pound, the molecule of which contains a portionwhich is aliphatically saturated and which is free from unsaturatedlinkages between acyclic carbon atoms, is reacted with oxalyl chloridein the presence of an organic peroxide. Saturated aliphatic andalicyclic hydrocarbons are readily converted to carboxylic acidchlorides. by this method. v

The following examples illustrate but donot limit the invention. weight.

Example 1 Some high boiling product is formed indicative' of theformation of methyl cyclohexane dicarboxylic acid chlorides.

Erample 2 55.6 parts of chlorocyclohexane and 25.4 parts All parts aregiven by 3 of oxalyl chloride and- 1.2 parts of benzoyl peroxide wereplaced in a reaction. container.

This mixture .was refluxed gently for 24 hours. At the completion of 24hours, the reaction mixture was fractionated in vacuo. A 60% yield ofchlorocyclohexane carboxylic acid chloride was obtained. Theidentification of the product was made by a determination of theneutralization equivalent. 1

Example 3.

25.2 parts of methyl cyclopentane, 25.4 parts of oxalyl chloride, and1.2 parts of benzoyl peroxide were placed in a reaction container. Itwas found desirable in all of these reactions to introduce the peroxidein small, portions over the entire reaction period. This mixture wasrefluxed gently for 24 hours. The yield of methyl cyclopentanecarboxylic acid chloride is 60%.

' Example 4 28.8 parts of normal pentane', 25.4 parts of I oxalylchloride, and 1.2 parts of benzoyl peroxide (added periodically in smallamounts) were placed in a reaction container.- This mixture was refluxedgently for 24 hours. hexanoic acid chloride was ,formed. The fact that ahexanoic acid chloride was formed 'was proved by a, determination of theneutralization equivalent of the acid.

Example 5 47 parts of toluene, 25.4 parts of oxalyl chloride, and 2.8parts of. benzoyl peroxide (added periodically in small portions) wereplaced in a reaction container. This mixture was refluxed gently for 24hours. hours, the excess of toluene was removed in vacuo. The acidchloride was then hydrolyzed with water and alkali. The alkalinesolution was acidified with H2504 and extracted with ethyl ether, Uponevaporation of the ether a product was obtained which uponcrystallization melted at 76 C., which is the melting'point of phenylacetic acid. The yield was 45%.

Example 6 v 90 parts or a saturated whitemineral oil, 25.4

parts of oxalyl chloride and 2.5 parts of lauroyl" peroxide (addedperiodically in small 'quantities) were placed in a reaction container.This A 40% yield of 7 At the completion. of 24.

placed in shire I was refluxed gently for 24 hours. The acid was mixturewas heated at 60-70" C. for 24 hours. The reaction mixture was treatedwith water and sodium carbonate and extracted with ligroin. The watersolution upon acidification yields a carboxylc acid of the white oil.

Example 7 v 99 parts of dodecyl benzene, 25.4 parts of oxalyl chloride,and 2.3 parts of benzoyl per-,

oxide (added periodically in small amounts) were placed in a reactioncontainer This mixture was heated gently at'80-90" C. for 24 hours.

At the end of that time, the unchanged dodecyl benzene and oxalylchloride were removed in vacuo. The residue was treated with water andsodium carbonate, and extracted with ethyl ether. Upon acidification thewater solution yielded phenyl dodecane carboxylic acid.

Example 8 101 parts oidodecyl cyclohexane, 25.4 parts of oxalylchloride, and-3.6 parts of benzoyl peretroleum fractions such assaturated gasolines, saturated kerosenes, saturated white oils, andparafiln waxes.

(2) Saturated alicyclic hydrocarbons, such as cyclohexane, methylcyclohexane, dodecyl cyclohexane, 'cyclopentane, methyl cyclopentane,

-menthane, camphane, naphthenes, and decahydronaphthalene.

(3) Alkyl halides, such as chlorocyclohexane, butyl chloride, dodecylbromide, cetyl chloride, and chlorinated. kerosene.

(4) Alkyl substituted aromatic hydrocarbons, such as toluene, propylbenzene, octyl benzene,

'decylbenzene, dodecyl benzene, hexadecyl benzene, amyl naphthalene,octyl naphthalene,

decyl naphthalene, dodecyl naphthalene, metal xylene, dibutyl benzene,dioctyl benzene, diootyl naphthalene, ;didecyl naphthalene, mesitylene,triamyl benzene, and tetraamyl benzene. This subclass includes mixturesof alkylated aromatic hydrocarbonswhich may be obtained by conoxide(added "periodically in small quantities) were placed in a reactioncontainer. This mixture heated at TO-90 C. for 24 hours. The dodecylcyclohexane' carboxylic acid was isolated according-kilo the proceduredescribed in Example 'l.

\ ,thiopheii'e, 25.4, parts of ox alyl chloride, arts oi-glauroylfperoxide (added periodic naniamounto were oncontainer. 'mixtureisolated as describediflip Example *1.

I Example 1'0, l 120 parts of paraflin wax, 25. 4 parts of oxalylchloride, and a total 014 parts? 01 benz'oyl peroxide (addedperiodically in small quantities) were placed in areaction container.This mixture was heatedatQO" C. for 24 hours. The acid was isolated asdeScribed in Example 'l.

Example 11 56.4 parts oi butylchloride', 25.4 parts of oxalyl chlorideand a total of 2.5 parts of benzoyl peroxide added periodically insmall. quantities) were placed in a reaction, container. This mixturewas refluxed gently for 24 hours. At the completion of 24 hours, theexcess of reagents was removed in vacuo, and the: product was isolatedby fractionation.

M The yields obtained vary considerably de, pending upon what reactantshave been selected. In many cases the yields are exceptionally highrunning .up to 85-90%. In Examples 1 to 5 the yields which are mentionedare based upon the amountoi oxalyl chloride actually consumed .in thereaction,

It will be noted from thaexamples that a large variety of compoundscan.be converted to carboxylic acid chlorides by the novel chemicaldensing chlorinated kerosenes or white oils with aromatic hydrocarbons,such as benzene, xylene,

and methyl naphthalene, by means of the Friedel-Craft reaction, and alsovarious alkylated aromatic hydrocarbons obtained-by alkylating benzeneor naphthalene with various mixtures oialcohols or mixtures of olefines.Whenthe compounds belonging in this subclass'are reacted with oxalylchloride in accordance with .thisinvention, substitution of the --COC1group generally occurs only in the aliphatic portion of cetyl alcohol,and mixtures of alcohols obtainable by catalytic hydrogenation oi higherfatty acids orinaturally occurring esters of the higher fatty ac ds.

(9) Aliphatic aldehydes, such as heptaldehyde and lauric aldehyde.

(10) Aliphatic ketones, such as none-8 and heptadecanone-B.

(11), Esters of aliphatic acids, such as methyl stearate', ethylpalmitate, and glycerides, such as lard, palm oil, and cocoanut oil.

(12), Acylated amines, such as N-dodecyl acetapentadeca- 'mide andN-cetyl propionamide.

(13') Heterocyclic compounds, such as ethyl thiophene, piperidine,acetyl piperidine, and decaprocess herein disclosed. In general, anyor-.

ganic compound, the molecule of which contains a portion which isaliphatically saturated and which is free from unsaturated linkagesbetween acyclic carbon atoms can be converted to a carboxylic acidchloride by this method. This category ofsuitable organic compoundsincludes a number of subclasses as indicated below.,

(1) Saturated aliphatics t r a ig h t and branched chain hydrocarbons,such as pentane, heptane, octane, isooctane, nonane, decane, dodecane;octane, octadecane,1 and saturated hydrocarbazole.

The compounds in the thirteen groupsset forth immediately above areexamples of organic compounds, the molecules of which contain a portionwhich is aliphatically saturated and which are free from unsaturatedlinkages between acyclic carbon atoms.

It is believed that the following theoretical explanation will helpenable the reader to further understand the present invention. It is tobe understood that if the following theoretical explanationis later'proven to be erroneous or fallacious it may be disregarded. The scope ofthe invention=as indicated by the disclosure in this specification andby the appended claims is not to be infected by any possible errors orfallacies in the following theoretical explanation.

It has been found that when oxalyl chloride is treated with an organicperoxide there results a free radical of the formula: .COCl and thisfree radical initiates a chain reaction which leads to the productionof. thecarboxylic acid chloride. This reaction may be illustrated by thefollowing:

decomposes Pb furnish P11 0001 Ph.COCl C001 COCl co 01 a We have foundorganic peroxides, such'as benzoyl peroxide, lauroyl peroxide, andascaridole, to be eii'ective catalysts for this reaction. When usingperoxides it has been found that it is generally desirable to add smallquantities of the peroxide to th reaction mixture periodically duringthe entire time that reaction is taking place.

The carboiwlic acid chlorides prepared according to the presentinvention maybe converted to the corresponding carboxylic acids or tothe salts, amides,- or esters of these acids. These acids, salts,amides, and esters are useful in many arts.-

Bcnzoyl peroxide One advantage of this invention is that it provides aone step method of preparing carboxylic acid chlorides from organiccompounds which initially contain no carboxyl group. Heretofore; in

the preparation of carboxylic acid chlorides it has generally been foundnecessary to first prepare the carboxylic acid'and then to react saidacid comes within the scope of the appended claims is to be regarded asan embodiment of this invention.

We claim:

1. A process of producing a carboxylic acid chloride which comprisesreacting oxalyl chloride with an organic compound which contains aportion whichis aliphatically saturated and which is free fromunsaturated linkages between acyclic carbon atoms in the. presence of anorganic peroxide.

2. A process of producing a carboxylic acid chloride which comprisesreacting oxalyl chloride with a hydrocarbon selected from the groupconsisting of saturated aliphatic and alicyclic hydrocarbons in thepresence of an organic peroxide. 7

MORRIS S. KHARASCH. HERBERT 0. BROWN.

